Behringer PMX2000 effects problem

[technoman28]

Hi folks, newbie here so be gentle!

I have a Behringer Europower PMX2000 mixer/amp, bought it dirt cheap as a non-functionong unit, all looked good inside ie no fried components etc and traced back to some dry joints on the power input board.
I managed to sort them out, and the unit works fine, apart from the effects section. The shaft of the effects pot is missing and when I turn on the unit, the DSP display shows (very, very briefly) F3, then the lights to the left of the display flash, then each section of the LED numbers display flashes and then cycles: "input LED's" >"left number LED" >"right number LED".

I have the schematics, but as I am not a whizz with electronic stuff, it does not mean that much to me. I am competant with soldering iron and confident enough to tackle most stuff with a bit of guidance/advice.

Do any of you have any ideas about what the problem could be, or point me in the right direction for any replacement (or alternative more likely) part for the FX pot. I am based in the north of the UK.

Thanks for reading this far.

[Martin Pedder]

I too am in the UK (Bury, near Manchester). I am not sure how much I can help you, but as a newcomer to this site you do at least deserve a welcoming reply from someone.

I think the "pot" you refer to is actually a rotary encoder, unless you mean the FX TO MON pot. The shaft being broken is probably your first clue. If it has had a bash, the remains of the pot or encoder may well be damaged, and the board behind it may also have suffered. Check every connection carefully around there looking for hairline fractures in the pcb and solder joints.

Behringer spares are famously hard to come by. There are authorised service agents on this forum who may be able to help. I have found PMS to be one of the few places for specific parts. PMS Shop Their shop is offline as I write this so I can't check if they do the shaft encoder.

Good luck.

[Enzo]

Go up to the Schematics Request section if the forum, and read the short thread about an LX1-12. (or something like that)

We identified he needed rotary encoders, and he found them at Mouser at my suggestion. Even if Mouser is not a good option in the UK, at least finding the part there would give you part numbers to search at your own suppliers.


Only snag I see is the selector encoders have a push switch if I recall correctly. Spin the control to select an effect number, then push down on the knob to enable the selection.

Your broken encoder could be confusing the system with loss of code, or the push switch part could be stuck shut.


A trick I use a lot when I need a new pot with plastic shaft because the old shaft is broken, and I don't have the right value pot... I find a wrong value pot of the same type, take it apart, and install the new shaft into the old pot. That assumes the old pot didn;t have a cracked wafer. If you can find the same encoder without push switch, you MIGHT be able to get it and take the shaft and install it into the old control, assuming the rest of the old control is not smashed.


Our friend and member John Frondelli sells Behringer parts.. I think his ENC-0139 might be your part.


Behr part number is: 832-32430-24605
Description: EC12E24244 12mm encoder 24 detent with push switch

Behringer Parts List

[technoman28]

I did have a look at the pot, and managed to make out the word "ALPS" on the body, which when googled came up with RS Components as a supplier, the only problem being that the list was massive, so I think I need to remove the pot from the board and see if I can find any more info.

The pot does incorporate a push switch and may well be the part you have listed Enzo. I also think you may be right about the "push" being stuck in. I will investigate further and report back, but in the meantime, thanks for the replies and help so far.

[Martin Pedder]

Lets start calling it a rotary encoder!

Try these people for the part.
Electronic Music Services - repairs to all major makes of electronic instruments

Martin

[Enzo]

RS is a big company and may have them, but as Martin says, call it a rotary encoder. One reason you got too massive a selection is because you were looking for "pots." Well, it isn't a pot. Search encoders instead.

[technoman28]

Enzo, the second part number on your post (the EC12E number), turned out to be the one I wanted, well almost, just slightly shorter shaft. Got it from RS for around £1.60 (inc post). All fitted and functioning perfectly. Thanks again to all who helped.

[sithering]

Hi guys

Did replacing the encoder fix the problem?

I've just bought a 2nd hand Eurorack 2442FX-Pro and it has the same issue as the OP. The Encoder knob is missing!

cheers, John

[sithering]

At the risk of answering my own question I have found out the fault described is actually the fx reset procedure designed by Behringer!

You activate it by switching on the mixer while holding down the fx button....and the display alternates between the 3 elements of the led! It's a stuck push-switch!

[pdf64]

...You activate it by switching on the mixer while holding down the fx button....and the display alternates between the 3 elements of the led! It's a stuck push-switch!

I was presented with a friend's PMX2000 that wouldn't power up, though the fuse was fine.
I fixed a simple bad solder joint on the fuse holder, and the unit powered up fine. However, the fx unit was stuck in F3, no fx type could be selected. A search brought up this thread, and the above reset procedure sorted it out, yey!
Many thanks to tboy for keeping this wonderful repository alive and well